Method for dispensing doses of coffee grounds

ABSTRACT

A method of controlling dispensing of doses of coffee grounds, the machine comprising a grinding device which is configured to grind coffee beans, a conduit, having an inlet in communication with the grinding device for receiving coffee grounds, and an outlet, a closure member which is adapted to be removed between an open position for the coffee grounds to be discharged from the conduit through the outlet, and a closed position for closing the outlet, and a coffee grounds weight sensor, which is configured to generate signals representative of the weight of coffee grounds built-up in the dispensing conduit when the closure member is in the closed position.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional of U.S. patent application Ser. No.15/828,981 filed Dec. 1, 2017 which claims priority from Italian PatentApplication Serial No. 102016000122725 filed Dec. 2, 2016, both of whichare incorporated herein by reference.

FIELD OF THE INVENTION

The present invention finds application in the field of grinding ofcoffee beans as is needed for preparation of a coffee beverage, e.g.espresso. Particularly, the invention relates to a method for controlleddispensing of doses of coffee grounds.

BACKGROUND ART

When preparing coffee beverages, such as espresso, coffee beans arefirst ground in a coffee grinder. Then the coffee grounds are brewedusing high-pressure hot water in a coffee machine. The coffee groundsejected by the coffee grinder is carried to the coffee machine into aportafilter, in which it is held even during preparation and dispensingof the beverage.

In order to obtain a coffee of the desired type, optimal adjustment ofprocess parameters is generally desired, such as the degree of grindingof coffee beans, pressing of the coffee grounds amount of coffee groundsin use, proper ground coffee-to-water ratio, and water temperature andpressure.

In a conventional grinding-dosing machine, coffee powder is filled in acollecting container and the barista allows coffee powder to be ejectedfrom the container into the portafilter, typically by actuating a lever.

IT1187064, for example, discloses an automatic coffee machine fordispensing coffee, which provides a consistent volume of brewed beverageand allows dispensing to be measured with time, such that the user ispromptly given an indication of the quality of the dispensed coffee.

On the other hand, ES1089030 discloses a coffee grinder thatincorporates a graduated transparent tube, allowing the amount of coffeethat is being ground to prepare a single coffee dose. Therefore, thebarista will receive a visual check of the amount of coffee grounds, andwill thus decide when he/she will manually act to turn off the coffeegrinder and stop grinding the coffee beans. The coffee dose is checkedbased on the volume of coffee that has been ground.

Professional grinding-dosing machines, e.g. for preparing doses ofcoffee grounds for espresso beverages from a coffee machine in a bar orrestaurant, are often configured to operate “on demand”, with coffeebeans being directly ground into the portafilter upon request.

In the coffee grinder as disclosed in EP2314188 the coffee dose to befed to the portafilter is adjusted based on preset grinding times. Thecoffee grinder may recognize the portafilter in use and autonomouslydecide the dose of coffee grounds to be dispensed. Each portafilter isassociated with a coffee dispenser, which dispenses coffee according toa predetermined recipe and, as the coffee grinder recognizes theportafilter, it will provide a provide a predetermined amount of coffeegrounds, e.g. a single or a double dose, associated with the recipe.

WO 2015/006244 discloses a coffee grinder equipped with a load cell thatsupports a fork for the barista to lay the portafilter thereon while thelatter is being filled with coffee grounds. This will deform the loadcell, and as its deformation is measured, the grinder will be able toprovide a measurement of the mass of the portafilter containing thecoffee grounds to the barista. Therefore, the mass of the coffee groundsis obtained by subtracting the mass of the empty portafilter from themeasured value. The coffee grinder as disclosed in this document alsoprovides arrangements to preserve the load cell from impacts that mightdamage it, particularly when the barista lays the portafilter on thefork. This is because the load cell should not be exposed to stressesthat are too higher than those expected for weighing.

US 2016/0143481 addresses a coffee grinding machine comprising adispensing conduit connected to a grinder unit for dispensing coffeeinto a filter supported by a portafilter supported by a platform,wherein a load cell is connected to the support platform for weighingthe amount of coffee contained in the filter. The load cell iselectrically connected to a control unit that receives measurementsignals indicative of the weight of coffee and is configured to stop thegrinder unit when the weight of the coffee attains a predeterminedvalue.

SUMMARY OF THE INVENTION

The Applicant found that measurement of the mass of the coffee groundsprovides, in certain cases of interest, more accurate dosing as comparedwith the control of the grinding time or the volume of coffee grounds.

The arrangements as disclosed in WO 2015/006244 and US 201610143481provide the possibility of measuring the mass of the coffee grounds. TheApplicant found that, since the devices as disclosed therein effectmeasurements with the weight of the portafilter supported by the loadcell, the mass of the empty portafilter has to be precisely known. Onecoffee grinder is generally used with various portafilters, whichusually have different masses. It shall be noted that a portafilter mayweigh a few hundred grams, and a dose of coffee grounds generally has amuch lower weight, e.g. a few grams. Therefore, even slight massdifferences between two portafilters, possibly of the same type, may besignificant as compared with the weight of the coffee to be dosed.

In the “on demand” operating mode, the machine can dispense doses ofcoffee grounds based on the grinding time. Dispensing is stopped uponexpiry of the time that has been set when programming the machine. Thesemachines are often equipped with a user interface which is used by auser to input the target dose, e.g. a single or double dose, andoptionally the degree of grinding. Typically, the coffee grounds isejected from a grinder unit into a filter within a portafilter via adispensing conduit.

Grinding time control may lead to dispensing of inaccurate doses ofcoffee grounds for various reasons. This is because coffee beans mayform agglomerates due to the effect of grease on the grains;furthermore, the coffee grinder is prone to wear, which leads to atime-dependent degradation of its operation parameters. Similar problemsmay cause changes in the degree of grinding or irregular sliding of theoutflowing coffee grounds from the coffee grinder, leading to dosingerrors.

Any changes in coffee mixtures or operating parameters of the machinemay affect the mass throughput, e.g. grams/second, of the coffee powderthat flows down through the dispensing conduit.

A change in the mass throughput may lead, under identical grinding timeconditions, to dispensing of a dose of coffee that deviates from thetarget value. A relatively slight deviation may affect the final resultin the cup. For example, an underbrewed or an overbrewed beverage may beobtained, with undesired organoleptic results.

If the machine has been set to dispense doses in a time-dependentmanner, dispensing of a dose other than the desired dose may beperceived only upon preparation of beverages whose taste or quality arenot as desired. Generally, the prepared beverage may be also visuallydifferent, and may fall from the machine with a stream other than a“mouse tail” stream.

On the other hand, adjustment and calibration of the machine by a userare often time-consuming operations, leading to downtime of thegrinding-dosing machine.

The Applicant realized that a procedure for automatic control of thedose being dispensed may afford an accurate check that the dose beingdispensed matches the nominal dose for a given coffee beverage.

The Applicant also realized that, by automatically weighing the coffeegrounds when the coffee has not being dropped into the portafilter yet,the “on demand” operating mode, only based on the grinding time, may bereplaced by a mode affording control of the dose that is being actuallydispensed without requiring coffee dose dispensing to be stopped.

The present disclosure provides a method of controlling dispensing ofcoffee grounds from a grinding-dosing machine, the machine comprising agrinding device which is configured to grind coffee beans, a conduit,having an inlet in communication with the grinding device for receivingcoffee grounds, and an outlet, a closure member which is adapted to beremoved between an open position for the coffee grounds to be dischargedfrom the conduit through the outlet, and a closed position for closingthe outlet, and a coffee grounds weight sensor, which is configured togenerate measurement signals representative of the weight of coffeegrounds built-up in the dispensing conduit when the closure member is inthe closed position, the method comprising: a) storing a nominal weightvalue of coffee grounds; b) storing a nominal grinding time valueassociated with the nominal weight value; c) placing the closure memberin the closed position; d) operating the grinding device for dischargingcoffee grounds through the conduit onto the closure member for a timeequal to the nominal grinding time value, in a first grinding operation;e) Receiving, at the end of the first grinding operation, a measurementsignal representative of an actual weight value of coffee groundsbuilt-up on the closure member; f) comparing the actual weight valuewith the stored nominal weight value and, based on the result of thecomparison, if the measured actual weight value differs from the nominalweight value to an extent exceeding a predetermined threshold value,calculating a mass throughput based on the actual weight value and thenominal grinding time value; g) based on the calculated mass throughputvalue, calculating an actual grinding time value to obtain the nominalvalue of the coffee grounds dose, and h) storing the actual grindingtime value as a new nominal grinding time value.

Preferably, the predetermined threshold value for deviation between thenominal weight value and the actual weight value is 10%, more preferably7%.

The flow throughput is calculated as a ratio of the actual weight valueto the nominal grinding time value as previously stored.

Preferably, before the step d), the method comprises receiving inputdata requesting coffee grounds dispensing, associated with the nominalweight value of coffee grounds, and the step d) is carried out inresponse to the reception of said input data.

In one embodiment, the machine comprises a portafilter-retaining supportand a presence sensor, which is configured to generate an electricsignal for notifying the presence of the portafilter when theportafilter has been placed in the retaining support, wherein the methodcomprises, before the step d), placing a portafilter on the retainingsupport, detecting the presence of the portafilter using the presencesensor, wherein receiving input data requesting coffee groundsdispensing associated with the nominal weight value comprises receivinga presence detection electric signal, wherein the grinding operationaccording to step d) is carried out in response to reception of thepresence detection signal.

A method of controlling dispensing of coffee grounds from agrinding-dosing machine, the machine comprising a grinding device whichis configured to grind coffee beans, a dispensing conduit, having aninlet in communication with the grinding device for receiving coffeegrounds, and an outlet, a closure member which is adapted to be removedbetween an open position for the coffee grounds to be discharged fromthe conduit through the outlet, and a closed position for closing theoutlet, and a coffee grounds weight sensor, which is configured togenerate signals representative of the weight of coffee grounds built-upin the dispensing conduit when the closure member is in the closedposition, the method comprising: storing a nominal weight value of thecoffee grounds and a nominal grinding time value, which are associatedwith a type of coffee-based beverage, (ii) placing the closure member inthe closed position; (iii) operating the grinding device for dischargingcoffee grounds through the dispensing conduit onto the closure memberfor a time equal to the nominal grinding time value; (iv) receiving ameasurement signal representative of an actual weight value of coffeegrounds built-up on the closure member at the end of the grindingoperation; (v) recording said measured actual weight value; (vi) movingthe closure member to the open position for the coffee grounds to bedischarged; (vii) repeating the steps (ii) to (vi) a plurality (N−1) oftimes, with N≥2, to record a plurality of N actual weight values at theend of N respective grinding operations; (viii) calculating a respectiveplurality of mass throughput values based on the plurality N of actualweight values and the nominal grinding time value; (ix) calculating anaverage mass throughput value front the plurality N of mass throughputvalues and an average weight value from the plurality N of measuredactual weight values; (x) comparing the average weight value with thestored nominal weight value and, if the average weight value differsfrom the nominal weight value to an extent exceeding a predeterminedthreshold value, calculating an average grinding time value, defined asa ratio of the nominal weight value to the calculated average massthroughput value, and (xi) storing said average grinding time value as anew nominal grinding time value.

Preferably, the N value is of from 2 to 10 μm.

Preferably, the predetermined threshold value for deviation between thenominal weight value and the actual weight value is 10%, more preferably7%.

According to the preferred embodiments of the invention, in the coffeedose control mode, the coffee grounds are weighed in a dispensingconduit that is held closed, where it builds up during grinding, and isthen discharged into the portafilter as the conduit is opened. During orat the end of grinding, the mass of coffee that has built up is weighedby means of a weight sensor.

Preferably, the weight sensor is a load cell, more preferably a bendingbeam load cell.

Preferably, the dispensing conduit and, as a result, the coffee groundsbuilding up therein upon the closure member, is supported on the loadcell in hanging relation. Particularly, the load cell comprises aflexible free end portion, which is mechanically connected to thedispensing conduit and to the closure member. This will afford accuratemeasurement and dosing of the mass of coffee grounds. Advantageously,the unladen mass as measured by the load cell is constant, which allowsa single measurement to be taken during calibration of the load cell.Therefore, the load cell may be set to indicate a zero mass in a no-loadmeasurement condition. Here, the mass that is being measured andindicated when coffee grounds are present directly corresponds to themass of the coffee grounds, and there is no need to check the unladenmass at each weighing operation, i.e. before dispensing the coffeegrounds, e.g. the mass of the portafilter.

Preferably, the closure member of the dispensing conduit is placed atthe outlet of the dispensing conduit.

Preferably, the measurement signal representative of the weight of thecoffee grounds built up in the dispensing conduit is an output electricsignal of the weight sensor.

Preferably, the grinding-dosing machine comprises an electronic controlunit, preferably a central processing unit (CPU), and the weight sensoris connected to the electronic control unit and is configured togenerate a measurement signal representative of the measured weight ofthe coffee grounds. For example, if the weight sensor is a bending beamload cell, the measurement signal representative of the weight of coffeegrounds is a voltage signal proportional to the deflection of the freeend portion, of the cell.

In certain embodiments, if the weight sensor is a load cell, thegrinding-dosing machine comprises a main body which comprises thedispensing conduit, the closure member and a load transfer structureattached to the free end portion of the load cell in such a manner as tobe supported in hanging relation by the load cell, with the dispensingconduit and the closure member being attached to the load transferstructure in such a manner as to be supported by the cell through theload transfer structure.

Preferably, the grinding-dosing comprises a drive system for driving theclosure member, the system comprising a motor driven by the electroniccontrol unit and connected to the closure member. The control unit isconfigured to control the movement of the closure member from the closedposition to the open position and vice versa.

Preferably, the grinding-dosing machine of the present disclosurefurther comprises a retaining support, which is configured to supportand/or mechanically connect a portafilter. The outlet of the dispensingconduit faces the retaining support, for the coffee grounds to bedischarged into the portafilter when the closure member is in the openposition The outlet of the conduit is preferably placed above theretaining support for the portafilter.

The present disclosure relates to a method of dispensing a dose ofcoffee grounds from a grinding-dosing machine, the machine comprising agrinding device for grinding coffee beans, a dispensing conduit, havingan inlet in communication with the grinding device for receiving coffeegrounds, and an outlet, a closure member which is adapted to be removedbetween an open position for the coffee grounds to be discharged fromthe conduit through the outlet, and a closed position for closing theoutlet, the method comprising: storing a buffer weight value and a firstgrinding time value associated with the buffer weight value; placing theclosure member in the closed position; carrying out a first grindingoperation, by operating the grinding device for a time equal to thefirst grinding time, for discharging coffee grounds through thedispensing conduit so that the amount of coffee grounds that build up onthe closure member corresponds to the buffer weight value; receivinginput data requesting coffee grounds dispensing, associated with anominal weight value of coffee grounds; comparing the received nominalweight value input with the buffer weight value; based on the comparisonresult, if the nominal weight value corresponds to the buffer weightvalue, placing the closure member in the open position to discharge thecoffee grounds built up at the end of the first grinding operationthrough the outlet of the dispensing conduit; based on the comparisonresult, if the nominal weight value is greater than the buffer weightvalue, carrying out the following steps: with the closure membermaintained in the closed position, carrying out a second grindingoperation by operating the grinding device to discharge coffee groundsthrough the conduit onto the closure member; stopping the grindingdevice when the built-up coffee is equal to the nominal weight value, orat the end of a grinding time associated with the nominal weight value,and placing the closure member in the open position to discharge thecoffee grounds built up at the end of the first and second grindingoperations through the outlet of the conduit.

Preferably, the buffer weight value corresponds to a single dose ofcoffee grounds. In certain embodiments, if the nominal weight value isgreater than the buffer weight value corresponds to a dose of coffeegrounds which is a multiple of the single dose.

In one embodiment, receiving input data requesting coffee groundsdispensing, associated with a nominal weight value of coffee grounds,comprises selecting a type of coffee beverage associated with saidnominal weight value.

In one embodiment, the portafilter comprises an identifier and thegrinding-dosing machine comprises an identification sensor, which isconfigured to read said identifier, when the portafilter is placed onthe retaining support of the portafilter, and to generate a signalrepresentative of the identifier. In this embodiment, receiving inputdata requesting coffee grounds dispensing associated with a nominalweight value of coffee grounds comprises receiving the signalrepresentative of the identifier of the portafilter and associating thereceived signal with a nominal value of coffee grounds, which has beenstored in the machine.

BRIEF DESCRIPTION OF THE FIGURES

Further features and advantages of the dosing device of this invention,will be apparent from the following description of one preferredembodiment thereof, which is given by way of illustration and withoutlimitation with reference to the accompanying figures, in which:

FIG. 1 shows a perspective view of a dosing device that may be includedin a grinding-dosing machine, according to one embodiment of the presentinvention,

FIG. 2 shows a perspective view of the dosing device of FIG. 1, whichcomprises a support frame according to a further embodiment of thepresent invention,

FIG. 3 is a rear perspective view of the dosing device of FIG. 2,

FIG. 4 is a side perspective view of the dosing device of FIG. 2,

FIG. 5 schematically shows a detail of a dosing device according to oneembodiment of the present invention,

FIG. 6 is a perspective view of a grinding-dosing machine according to apreferred embodiment of the present invention,

FIG. 7 is a block diagram of a system for controlling grinding andweighing of the coffee grounds with reference to the grinding-dosingmachine of FIG. 6, and

FIG. 8 is a schematic view of an example of a portafilter.

DETAILED DESCRIPTION

FIG. 1 shows a perspective view of a dosing device 3 that may beincluded in a grinding-dosing machine (not shown in FIGS. 1 to 5),according to one embodiment of the present invention. The dosing device3 comprises a main body 5. The main body 5 comprises a dispensingconduit 51 having one inlet 52 and one outlet 53. The inlet 52 isconfigured to receive coffee grounds, e.g. from a coffee grindingdevice. The outlet 53 of the conduit 51 is configured to allow coffeegrounds to be discharged from the conduit 51. The dispensing conduit 51preferably extends in the vertical direction between the inlet 52 andthe outlet 53. The coffee grounds received through the inlet 52 fall bygravity along the conduit 51 out of the outlet 53.

In certain embodiments, the dosing device 3 is configured to dischargepredefined doses, of coffee grounds, The dosed coffee grounds dischargedfrom the dosing device 3 may be collected in a portafilter, typicallysupported by a retaining support (not shown in FIG. 1), such as a fork.

The main body 5 of the dosing device 3 comprises a closure member 54which is preferably placed at the outlet 53 of the conduit 51. Theclosure member 54 is able to move between a closed position and an openposition. In the embodiment as shown in the figures, the closure member54 is a plate, e.g. a steel plate.

In the closed position, the closure member 54 prevents coffee groundsfrom being discharged out of the outlet 53 and allows coffee grounds tobuild up in the dispensing conduit 51. Preferably, in the closedposition, the closure member closes the outlet 53 and supports thecoffee grounds built up in the conduit 51. Conversely, in the openposition, the closure member leaves the outlet 53 open, allowing coffeegrounds to be discharged from the conduit 51 through the outlet, in thedirection of the arrow 99.

In the examples as shown in FIGS. 1-4, the plate 54 is mounted to a pin88 which acts as a fulcrum for pivoting about an axis of rotation AA andswitching between the closed position and the open position is performedby rotating the plate from a horizontal position in which it closes theoutlet of the conduit and a vertical position (substantially along themain direction of extension of the conduit, i.e. the direction 99) inwhich it leaves the outlet 53 open. It should be appreciated that,although preferred, the open position must not necessarily be in a planesubstantially perpendicular to the plane in which the plate is in theclosed position.

The dosing device 3 comprises a weight sensor 6 configured to generateelectric measurement signals representative of the weight of the coffeebuilt up in the dispensing conduit. Preferably, the weight sensor is aload cell 6, which is configured to measure the weight of the coffeegrounds built up in the dispensing conduit 51 when the closure member 54is in the closed position. Particularly, the load cell 6 comprises afree first end portion 61 and a second end portion 62 opposite thereto.

Preferably, the load cell is a bending beam load cell or a shear beamload cell. The load cell 6 generally comprises at least one flexibleportion 63 situated between the first end portion 61 and the second endportion 62, and configured to deform under the weight applied to thefirst end portion 61. Furthermore, the load cell 6 may comprise one ormore strain gages (not shown) applied to the flexible portion 63 andconfigured to generate a voltage signal proportional to the deformationof the flexible portion 62. Strain gages may be. for example, deformableresistors connected in a Wheatstone-bridge configuration, according toknown techniques.

The load cell is connected to an electronic control unit (not shown inFIGS. 1-6), preferably a central processing unit (CPU), which isconfigured to receive the measurement signals representative of the loadapplied to the cell generated by the weight sensor. For example, theload cell is electronically connected to the electronic control unit forreceiving voltage signals proportional to the deformation of die loadcell and possibly for transmitting control signals to the sensor.

The first end portion 61 is flexible and is connected to the main body 5of the dosing device in such a manner as to support the main body 5 inhanging relation. In other words, the main body 5 hangs from the firstend portion 61 of the load cell 6. Thus, the weight of the main body 5and of the coffee built up in the main conduit 51 rests completely onthe load cell 6, thereby causing the deformation of the flexible portion62 and thus allowing the measurement of such weight, e.g. by means ofthe strain gages.

The load cell 6 is preferably configured to measure the weight of thecoffee grounds built up in the conduit 51 of the main body 5 bydifference between a gross weight of the main body 5, as measured whenthere are coffee grounds in the conduit 51 of the main body 5, and atare weight constituted by the main body 5 itself with no coffee groundsin the conduit. The tare, that may be measured when the dispensingconduit 51 of the main body is empty, may be thus represented by aconstant numerical value. The load cell 6 may be configured to indicatea zero weight when no coffee grounds are present in the conduit 51.Thus, the measurement signals transmitted by the load cell to the CPUare representative of the weight of the coffee built up in the conduit.

It will be appreciated that the load cell may operate in a relativelynarrow range of values and provide adequately precise measurements. Theload cell initially supports a main body that comprises the dispensingconduit and the mass of the coffee grounds is simply later added to suchmass. Therefore, the mass increase recorded by the cell duringmeasurement is only equal to the quantity to be measured, i.e. the massof the coffee grounds, As a result, from an equilibrium position assumedby the load cell before grinding, the load cell is subjected to a smalldeformation when the coffee grounds are present.

As further discussed hereinafter, the second end portion 62 of the loadcell 6 during use is fixed, particularly by means of a stable connectionwith a structure external to the main body, referred to hereinafter assupport structure, e.g. a non-hanging panel or frame, such as a frame ofa grinding-dosing machine that comprises the dosing device of thepresent disclosure.

In a preferred embodiment, the main body 5 comprises a load transferstructure 55. In the embodiment as shown in the figures, the loadtransfer structure 55 is shaped as a suitably shaped plate. Preferably,the load transfer structure 55 has a vertically-oriented main plane ofextension (i.e., parallel to the main direction of extension of theconduit 51) and comprises at least one connecting portion 92 projectingout of the main plane of extension for attaching the structure 55 to theload cell 6, particularly the first free end portion, 61 of the cell 6.More generally, the load transfer structure 55 is attached to the firstend portion, 61 of the cell 6, as discussed in greater detail below.

In the embodiment as shown in the figures, the load transfer structure55 comprises an opening 77 which is configured to receive the load cell6 in a transverse position across the opening. The load cell 6 isarranged to project out of the main plane of extension of the loadtransfer structure 55, and particularly both end portions of the loadcell are arranged to project out of the main plane of extension of theload transfer structure. The dispensing conduit 51 and the closuremember 54 are engaged on the load transfer structure 55, and areparticularly attached to it. For example, the conduit 51 is attached tothe load transfer structure 55 through first fastener elements.

In the exemplary implementation of the figures, the main body 5comprises an outlet connection clement 91 disposed at the outlet 53 ofthe conduit 51 and connected to the outlet. Preferably, the outletconnection element 91 is formed of one piece with the conduit 51. Theoutlet connection element 91 is hollow and has an opening at the outlet53 of the conduit to allow ejection of the coffee grounds from theconduit through the connection element.

In the illustrated embodiment, without limitation, the outlet connectionelement 91 extends outside the conduit 51, in a main directionperpendicular to the longitudinal axis of the dispensing conduit 51. Afirst connecting flange 90, which projects out of the main plane ofextension of the structure 55, is attached to the structure or isintegral with the structure. The first connecting flange 90 isconfigured to support the outlet connection element 91, and be attachedthereto by first fastener means 89 (e.g. a plurality of screws into afastening box). Accordingly, the conduit 51 is supported by the loadtransfer structure 55 through the outlet connection element 91, thefirst fastener means 89 and the first connecting flange 90.

It shall be understood that other methods of connection, namelyfixation, may be provided between the dispensing conduit 51 and the loadtransfer structure 55, other than those as shown in the figures.Particularly, the outlet connection element 91 is optional, and theconnection flange 90 is also optional.

In the embodiments of FIGS. 1-4, the plate 54 is attached to the loadtransfer structure 55 by means of a pivot or pin 88 for pivoting aboutthe axis AA, which moves the plate 54 from the closed position to theopen position.

In an alternative embodiment, a detail whereof is schematically shown inFIG. 5, described in further detail hereinbelow, the closure member 54is movable relative to the load transfer structure 55 in the straightdirection.

The load transfer structure 55 is attached to the first end portion 61of the load cell 6. Particularly, the first end portion, 61 of the cell6 comprises a supporting surface 64 for application of bending stresses.

In the illustrated example, the load transfer structure 55 is attachedto such bearing surface 64 by means of second fastener elements 65, e.g.screws. Particularly, the connection portion 92 of the structure 55 isattached to the first end portion 61 of the cell 6. Thus, the loadtransfer structure 55 is supported in hanging relation on the supportsurface of the load cell 6 and in turn, the conduit 51 and the closuremember 54 are constrained to the load transfer structure 55, and arehence supported by the load cell 6 in hanging relation through thestructure 55.

As mentioned above, the second end portion 62 of the load cell 6 can befixed to a support structure for supporting the load cell 6, whichsupports the main body 5 in hanging relation by its free first endportion. As more clearly explained hereinbelow, the support structuredoes not hang from the load cell 6. Preferably, the support structurerests on or is attached to a base.

Referring to the embodiment of FIGS. 2-4, the support structure, whichis external to the main body, is a panel 8 that is supported or fixed toa base, in the work position of the dosing device, to thereby supportthe main body. Preferably the panel 8 is formed as a suitably shapedplate. The second end portion 62 of the load cell 6 is attached to thepanel 8 of the dosing device 3. The panel 8 is preferably asubstantially flat panel, which is located behind the load transferstructure 55, and with a vertical orientation, for the main body 5 to bearranged to project out of the panel 8. In the illustrated embodiments,the main body 5 comprises at least one portion projecting out of thepanel 8, such portion, comprising at least the conduit 51 and theclosure member 54.

The panel of the dosing device 3 may be stably supported or bemechanically connected to a frame (not shown in FIGS. 1-5) of agrinding-dosing machine, which comprises the dosing device 3. The secondend 62 of the load cell 6 may be connected to the frame eitherindirectly through the panel 8 of the dosing device 3 (like in theexample as shown in the figures) or directly. The panel 8 supports theload transfer structure 55. Since the panel 8 rests on a base and/or isattached to a frame, it is not weighed by the load cell 6.

Preferably, the load cell 6 is arranged to project out of the panel 8.The panel 8 has an opening 82, at the opening 77 of the load transferstructure 55, for the passage of the load cell 6 through the openings,with the load cell 6 not contacting the edge of the opening 82, to avoidmeasurement errors.

The panel 8 is attached to the load transfer structure 55 and hence tothe main body 5 by the second end portion 62 of the load cell 6. Sinceno other constraint points are provided between the load cell and astructure external to the main body, the load transfer structure issupported in hanging relation on the flexible and free first end portion61 of the load cell and is free to move relative to the panel 8.

Preferably, the movement of the load transfer structure and hence themain body is vertically restricted by first limit-stop elements, andmore preferably is also horizontally restricted by second limit-stopelements. The first limit-stop elements, and the second limit-stopelements, if any, are configured to restrict the, movement of the mainbody 5 and the panel 8 relative to each other, to thereby protect theload cell 6 from excessive deformations as a result of accidental damageto the main body 5.

In the embodiment as shown in the figures, first limit-stop elementscomprise limit-stop screws 57 and respective abutment surfaces 84. Thescrews 57 of the first limit-stop elements are arranged in such a manneras to be spaced from the abutment surfaces 84 when no impact occurs, andto contact their respective abutment surfaces 84 in the case of impacts,to thereby restrict the movement of the main body 5 and the panel 8relative to each other. Namely, the limit-stop screws 57 are fixed tothe upper portion and the lower portion of the load transfer structure55, and particularly to respective flanges formed in the structure 55 atrespective holes in the panel 8. For example, the abutment surfaces 84horizontally project out of the panel 8. Each screw 57 of the main body5 has an abutment surface 84 of the panel 8 corresponding thereto, toallow the main body 5 to move relative to the panel in the verticaldirection, before stopping its movement.

Preferably, the movement of the main body is restricted in thehorizontal direction by second limit-stop elements, for instancelimit-stop screws 85 attached to the panel 8, proximate to the verticalwalls of the load transfer structure. Each screw 85 of the panel has anabutment surface of the main body 5 corresponding thereto, for instancea vertical portion of the load transfer structure 55.

It shall be appreciated that, by defining the load transfer structurethat holds the main body (open conduit) as the tare, the movement causedby (further) bending of the free end portion of the load cell forweighing the coffee grounds is relatively small, considering typicalcoffee grounds masses dispensed into a portafilter ranging from 5 to 30grams.

In the exemplary implementation as shown in the figures, the second endportion 62 of the load cell 6 is attached to the back surface of thepanel 8, opposite to the front surface on which the load transferstructure 55 is arranged to project (as shown in FIGS. 3 and 4). Thepanel comprises a connection flange 81, projecting out of the main planeof extension of the panel 8, which can be made by cutting and bending aportion of the panel 8. The second end portion 62 of the load cell 6rests on, and is preferably fastened to a plate 93 that rests on theconnection flange 81, disposed below and parallel to the plate 93 andspaced from the latter through the use of damping elements 67. The endsof these damping elements are fastened to the plate 93 and the flange81, by means of screws 96 and nuts 66 respectively.

It shall be understood that other ways of fastening the second endportion 62 of the load cell 6 are possible. For example the second endportion may be fixed to a flange, which is in turn fixed to the backsurface of the panel (not shown). The damping elements 67 are optionaland the provision of both a plate and a flange for attaching the secondend 62 of the load cell to the panel is also optional.

As discussed in greater detail below, in certain embodiments, the panel8 is preferably configured for connection with a support structure thatis external to the dosing device. For this purpose and according to theexample of FIGS. 2-4, the panel has connection elements 83 and 83′.

Preferably, the main body 5 comprises a drive system 7 which isconfigured to move the closure member 54 between the open position andthe closed position. The drive system 7 is connected to the loadtransfer structure 55. It will be appreciated that the mass as measuredby the load cell 6 is also inclusive of the mass of the drive system 7.Preferably, the drive system 7 comprises a motor 71 connected to theplate 54.

In the embodiment as shown in FIGS. 1 to 4, the drive system 7 comprisesa first pulley 72 driven by the motor 71, a second pulley 73 which isfixed to the pivot 88 and pivots relative thereto, to thereby rotate theclosure member 54, and a drive belt 74 for transferring the rotarymotion from the first pulley 72 to the second pulley 73, i.e. from themotor 71 to the closure member 54, to thereby move the closure member 54between the open position and the closed position.

In a further embodiment, as schematically shown in FIG. 5, the drivesystem 7 comprises a cogwheel 75 coupled to a motor 71, and a rack 76.The rack 76 cooperates with the cogwheel 75 to convert the rotary motionof the toothed wheel into a rectilinear motion, such that the motor 71will move the closure member 54, for instance a plate, between the openposition and the closed position in the direction B, in both ways. Thedirection of movement of the plate is horizontal, i.e. perpendicular tothe main extent of the dispensing conduit 51. The arrow E indicates thedirection of discharge of coffee grounds along the dispensing conduit.

The dosing device of the present disclosure is included in agrinding-dosing machine, which comprises a coffee bean grinding device.

Preferably, the grinding-dosing machine comprises an electronic controlunit (not shown in FIGS. 1-6) connected to the load cell 6 and to thedrive system 7. The control unit is configured to actuate the drivesystem 7, and in particular the motor 71, to thereby move the closuremember 54 from the open position to the closed position and vice versa.

FIG. 6 is a perspective view of a coffee grinding-dosing machine,according to one embodiment. The grinding-dosing machine 1 comprises acoffee bean grinding device, or grinding device 2 and a dosing device,and particularly the dosing device 3 according to the embodiment asshown in FIGS. 2-4. The same reference numerals indicate the sameelements or elements having the same function. It shall be understoodthat the machine may comprise a dosing device according to a differentembodiment of the present disclosure.

The grinding device 2 has known characteristics, some of which aredescribed in any case, for better understanding of the operation of thedosing device 3.

The grinding-dosing machine comprises a vessel (not shown in FIG. 6),for instance formed as a hopper, in which coffee beans can be depositedfor later grinding, and which can be coupled to a coupling member 86.The grinding device is in communication with the vessel to receive thedeposited coffee beans therefrom. The grinding device comprises agrinder unit (not shown) which is designed to be driven by a motor 21,Conventionally, the grinder unit comprises one or more grinding wheels(e.g. A pair of flat or cylindrical grinding wheels) or one or morerelatively rotating blades for grinding coffee beans.

The grinding-dosing machine 1 comprises a frame 95 that supports thebean-containing vessel and the grinding device 2. The frame 95 comprisesa base 94 upon which the machine lies, The coffee grounds are ejectedfrom the grinder unit which is connected with the inlet 52 of thedispensing conduit 51 of the dosing device 3. Particularly, the grinderunit introduces coffee grounds into a connecting duct, e.g. a chute 87,connected to the conduit 51.

An optional conduit 23 connects the conduit 51 to the upper surface ofthe grinder-doser 1 to afford cleaning thereof without disassembling themachine.

The machine 1 further comprises a retaining support 24, which isconfigured to support and/or mechanically connect a portafilter 4. Forexample, the retaining support is a fork, on which the portafilter islaid. Preferably, the outlet 53 of the conduit 51 faces the retainingsupport 24 to allow coffee grounds to be discharged into the portafilterthat rests on or is connected to it, when the closure member 54 is inthe open position. The dosing device 3 is placed on the portafilterretaining support 24.

The panel 8 is mounted in the housing of the machine 1 and ismechanically connected to a support structure of the machine 1, which isexternal to the dosing device. In FIG. 6, the panel 8 is attached to aportion 22 of the frame 95 of the machine by means of connectingelements 83. In the embodiment of the figures, the panel 8 comprisesadditional connecting elements, e.g. coupling teeth 83′ as shown inFIGS. 2 and 4, for the panel 8 to be coupled to the base 94 of thegrinding-dosing machine 1 and preferably, to an optional sealing flange103 of the portafilter 4.

In another embodiment, the panel 8 is only attached to the base 94 ofthe frame of the machine 1.

It shall be understood that the load transfer structure 55 may besupported and/or mechanically connected to a panel 8 having aconfiguration other than that shown in the figures or, as mentionedabove, be supported and/or directly connected to a fixed structureexternal to the dosing device 3, such as a frame of a machine thathouses the dosing device. In the latter case, the panel 8 will not benecessarily provided.

In one embodiment (not shown), the second end portion 62 is directlyattached to a portion of frame 95 of the grinding-dosing machine.

It shall be noted that, since the portafilter 4 is not designed to reston any part of the main body 5 or the load cell 6, the dosing device 3may be configured in such a manner that the mass of the main body 5 willremain substantially constant throughout the useful life of the dosingdevice 3 or at least for an extended use of the device.

FIG. 7 is a block diagram of a system for controlling grinding andweighing of the coffee grounds. The machine is equipped with anelectronic control unit, e.g. a central processing unit, CPU 97, and auser interface 98 which is electronically connected to the control unit.Conventionally, the user interface may be a touch-screen display or akeypad through which the user can input commands and/or enter inputdata. The control unit, which is usually housed in the machine and theuser interface, typically arranged on an outer front panel of themachine for easy access by a user, are not shown in FIG. 6. The motor 21of the grinder unit and the motor 71 which moves the closure member 54,as schematically shown in FIG. 7, are controlled by the CPU 97. The CPUis configured to receive electric measurement signals representative ofthe weight by the weight sensor 6 and to transmit control signals to theweight sensor, to the motor of the grinder unit 21 and to the motor 71for driving the closure member 54. The control signal lines from/to theCPU 97 are shown in FIG. 7 by a dashed line.

In one embodiment, the control unit controls the operation of thegrinder unit of the grinding device 2, through the grinder motor 21.Namely, the control unit is configured to start a grinding operation andstop a grinding operation when the weight of the coffee grounds attainsa default value or when a delimit time interval expires. The defaulttime and/or weight values may be either selected by the user or storedin the control unit. The default values, hereinafter also referred to asnominal values can be entered as input data that are received by the CPUor stored in the CPU. The nominal weight and/or time values may varyaccording to the desired coffee recipe.

The grinding-dosing machine may be equipped with means, known per se,for recognizing a portafilter, and the control unit is configured toassociate different default coffee weight values with differentportafilters. FIG. 8 shows an exemplary portafilter 100, which may havean identifier 101 (schematically shown), which is preferably removable,and is preferably placed on the basket 102 for recognition by a sensor.While the identifier is shown in a lateral region of the basket of theportafilter, the identifier can be placed on the front of the basket 102(not shown in FIG. 8). The identifier 101 may be an optical identifier,such as a color or any other prior art means, such as a barcode, aninductive means or a mechanical code with which the recognition sensorinteracts. Referring to FIG. 6, when the filter holder 100 is placed onthe fork 24, a presence sensor (not shown), e.g. of inductive type,detects the presence of the portafilter. The presence sensor isconfigured to generate an electric presence signal and is connected withthe CPU. A recognition sensor (not shown), e.g. placed below the sealingflange 103, at the identifier of the portafilter, detects coffee groundsdispensing type, e.g. total mass to be dispensed and, optionally, thedegree of grinding. The, recognition sensor is configured to generate anelectric portafilter recognition signal. As the presence of theportafilter is detected, the presence sensor transmits an electricpresence detection signal to the control unit. The CPU is configured toreceive the portafilter identification signal in addition to thepresence detection signal and, as upon reception of these signals, tocontrol a grinding operation according to the dispensing type associatedwith the identifier. Conventionally, the electronic control unit storesa data table that contains a plurality of identifier data associatedwith a respective plurality of portafilter identifiers, with each dataidentifier being associated with a nominal dose of coffee grounds.

Preferably, before using the grinding-dosing machine, e.g. during theinstallation of the machine, an operator calibrates the dosing devicefor the load cell to read a zero weight value when no coffee grounds arepresent in the dispensing conduit. Preferably, the operator sets anominal coffee grounds weight value.

In one embodiment, the operator enters a nominal weight value as aninput data into the user interface 98 and starts a grinding operationfor an initial configuration of the machine. The CPU is configured toreceive the nominal weight value entered by the user and, once thegrinding operation has been selected, to carry out the operation withthe plate in the closed position and to check the weight of coffeegrounds on the plate, as the operation is being carried out. When theweight of the coffee that falls on the plate attains the nominal weightvalue that has been previously set, the grinding operation is stoppedand the control unit is configured to determine the grinding timeassociated with the nominal weight value and to store this value as anominal grinding time value. The nominal weight value and the associatednominal grinding time value are stored in the CPU. The CPU is preferablyconfigured for calculating, based on these values, a nominal massthroughput of coffee grounds, e.g. in grams per second.

The CPU is preferably configured to store a plurality of nominal weightsof coffee grounds associated with a corresponding plurality of nominalgrinding times, for example depending on the type of beverage to beprepared. According to the nominal weight values stored, the controlunit may be configured to determine a respective plurality of massthroughputs or grinding times. If a plurality of types of beverages areprovided, the control unit is preferably configured to create, an inputdata table, listing nominal weight values and associated nominal massthroughput (or nominal grinding time) values, for each type of beverage,as acquired as a result of respective calibration operations.

The selection of the type of beverage and hence the selection of thenominal weight, time and possibly mass throughput, may be made manuallyor through automatic recognition of the portafilter, as described above.

After the initial configuration of the machine, and according to oneembodiment of the machine, the latter works “on demand” and the dosingdevice operates with the coffee grounds dispensing conduit always open,namely the control unit is configured to hold the plate in the openposition. In this mode, the dispensed dose is a function of the grindingtime stored in the machine for a particular type of beverage.

The Applicant found that during use of the grinding-dosing machine in adispensing mode that relies on the grinding time, the operatingconditions may change over time of use of the machine, which will allowthe dispensed dose to no longer correspond, to the desired dose set by auser or stored in the machine.

Preferably, the weight of coffee grounds being dispensed is controlledautomatically. In an “on demand” mode of use of the grinding-dosingmachine, such control may be actuated after a given time of use of themachine (e.g. after a few hours, one day or one week). The weight of thedispensed dose may be controlled in a single dispensing operation or, ina preferred embodiment, over a plurality of dispensing operations.

In one embodiment, the electronic control unit is configured to: (a)setting the closed position of the plate; (b) receiving input dataindicative of the type of beverage (e.g. single espresso, doubleespresso, American coffee), said input data being associated with anominal coffee grounds weight value, W_(N), and with a first grindingtime value, t₁, that have been stored and, preferably, calculating anominal mass throughput, Q_(n)=W_(n)/t₁; c) controlling a grindingoperation having a duration equal to the first grinding time value, t₁;(d) measuring an actual coffee grounds weight value, W_(r), at the endof the grinding operation; (e) comparing the actual weight value W_(r)with the nominal weight value W_(n); (f) based on the result of thecomparison, if the value W_(r) differs from W_(n) above a predeterminedthreshold value, determining a value of the actual mass throughput,Q_(r)=W_(r)/t₁, based on the actual weight value and the first grindingtime value, and (g) setting the grinding time to a second grinding timevalue, t₂, to obtain the nominal value of the dose of coffee grounds,W_(n). The second grinding time value is calculated based on the valueof the actual mass throughput, T₂=W_(n)/Q_(r).

The second grinding time value, t₂, is stored in the control unit inplace of the first grinding time value.

The first grinding time value, t₁, may correspond to the nominal timevalue that has been set in the machine upon calibration.

The electronic control unit may be configured to record the actualweight value W_(r) before comparing this value with the nominal weightvalue W_(n).

The steps (a) and (b) may be exchanged in order.

The step (d) is carried out by receiving an electric measurement signalgenerated by the weight sensor, and representative of the actual weightvalue.

Preferably, the control unit is configured to control the openingmovement of the plate, after the step (d). It shall be understood thatthe plate may be moved to the open position after one of the stepsfollowing the step (d).

Preferably, the control unit is configured to control a new grindingoperation for a the grinding time equal to the second grinding time, t₂,once the conduit has been opened.

The mode of operation of the grinding-dosing machine as described abovewith reference to steps (a) to (g) may be used to check calibration ofthe machine and/or proper operation of the grinding-dosing machine. Theoperator can start the automatic procedure comprising the steps (a) to(g) by selecting a command in the user interface. With no request beingmade by the user, the plate 54 is kept open, and the coffee is groundfor a default stored time, which may selected according to the beveragetype. Upon request by the user, the plate 54 closes for a singlegrinding operation, allowing the weight of the coffee grounds to bemeasured and a new grinding time to be stored. Once the operator haschecked that the correct mass has been dispensed in one dose, he/she mayswitch the grinding-dosing machine back to the “on demand” operation,with the closure member 54 always open during grinding and preferablybetween successive grinding operations.

In the above described mode of operation, the “correct” grinding time iscalculated based on a previous grinding operation. For example, if thenominal mass throughput value Q_(n) is 2 g/s and the nominal weightvalue W_(n) is 10 grams of coffee, the nominal grinding time initiallyset in the control unit is t_(n)=t₁=5 seconds. If, after a grindingoperation, the measured weight value is W_(r)=7 grams (other than thenominal weight), the mass throughput, for the nominal time of 5 seconds,is Q_(r)=1.4 g/s. In order to obtain the nominal weight of 10 g, thegrinding time will be adjusted to a value t₂=7 seconds, which accountsfor the mass throughput change.

Preferably, the stored time is changed if the measured weight of thecoffee grounds differs from the value of the nominal weight by at leasta default threshold value of 10%, more preferably of 7%.

According to a further embodiment, the weight of the coffee grounds ismeasured after a plurality N of dispensing operations of dosesassociated with the same dispensing/drink type. In this embodiment, thegrinding-dosing machine is configured to open and close the closuremember at each dispensing operation for the plurality of dispensingoperations associated with the same dispensing type. The control unit isconfigured to store a nominal weight value, W_(N), and a nominalgrinding time value, t_(n), and to determine a nominal mass throughputvalue, Q_(n)=W_(n)/t_(n). The control unit is configured to: i) move theclosure member to the dosed position, ii) carry out a grinding operationhaving a duration equal to the nominal grinding time t_(n) such that thecoffee grounds will deposit on the closure member; (iii) receive ameasurement signal representative of the actual weight value of coffeegrounds built up on the closure member at the end of the grindingoperation and record the actual value of the measured weight, W_(R), and(iv) move the closure member to the open position to discharge thecoffee grounds.

The control unit is configured to carry out the operating steps (i) to(iv) for N grinding operations, to thereby record, for each operation,an actual measured weight value, W_(R).

Then, at the end of a plurality N of grinding operations and storage ofa respective plurality of actual weight values (W_(R))_(i) with i=1, . .. , N, the electronic control unit is configured to calculate arespective plurality of values of mass throughput (Q_(r)), based on theactual measured weight values and the nominal grinding time, t_(n), andto calculate the average mass throughput value Q of the plurality ofvalues of the mass throughput and the average actual dose value, W _(r).Preferably, N ranges from 2 to 10, e.g. 5.

If the average weight W _(r) deviates from the nominal weight valueW_(n) above a predetermined threshold value, the control unit isconfigured to adjust the grinding time to a grinding time value that hasbeen determined by the ratio of the nominal weight, W_(N) to the averagemass throughput value Q. Preferably, the predetermined threshold valuefor deviation between the nominal weight and the average actual value is10%, more preferably 7%.

Since one or more of the operating conditions of the machine mightchange during the time of use thereof, the above discussed procedure canprovide a new grinding time value that more closely corresponds to thedesired dose of coffee grounds. Said determined grinding time is storedin the control unit for later coffee grounds dispensing operations.

The mode of operation of the grinding-dosing machine as described abovewith the dispensed dose being weighed for a plurality of N grindingoperations, may be used to check calibration of the machine and/orproper operation of the grinding-dosing machine. The operator may startthe automatic procedure by selecting a control in the user interface. Incertain embodiments, with no request being made by the user, the plate54 is kept open, and the coffee is ground for a default stored time,which may selected according to the beverage type. Upon request by theuser, the plate 54 closes and opens for a plurality N of windingoperations for a beverage type, and a new grinding time for thatbeverage type is later stored. Once the operator has checked that thecorrect average mass has been dispensed in a plurality of doses, he/shemay switch the grinding-dosing machine back to the “on demand”operation, with the closure member 54 always open during grinding andpreferably between successive grinding operations.

Since the N dispensing operations from which the average weight valuehas to be calculated and the actual average mass throughput areassociated with a given type of beverage and hence with a given nominaldose value, such plurality of dispensing operations may not besuccessive. For example, two types of dispensing operations areprovided, i.e. dose A (e.g. single espresso) and dose B double espressoor two single espressos). Depending on requirements, the grinding-dosingmachine, which has been set. in weight control mode, is controlled tosuccessively dispense 3 doses A of coffee, 4 doses B of coffee and 2doses A. If the number N of dispensing operations for the dose A,designed for average weight control has been set to 5, at the end of thelast dispensing operation for the dose A, the control unit carries outthe above described averaging procedure and stores the actual grindingtime value, if any, as a new nominal grinding time value.

In the above described mode of operation, the “correct” grinding time iscalculated based on N previous grinding operations.

In a conventional grinding-dosing machine, the coffee powder iscollected in a container. This filling, operation may be carried outautomatically or manually and the coffee grounds content typicallyranges from 100 to 200 grams. While the use of such grinding-dosingmachine provides the advantage of allowing the portafilter to be filledwith coffee powder in a relatively short time, the permanence of thecoffee grounds in the collection container, for a relatively long timeand in the presence of air and moisture, can cause a degradation of theorganoleptic characteristics of coffee.

The Applicant found that, while an “on demand” grinding-dosing machinedoes not involve coffee grounds build-up, instant grinding of coffeecauses the dispensing time for a dose of coffee grounds to be longerthan the time required for the ejection of coffee grounds from acollection container. By way of illustration and example, thepreparation of a dose for a single espresso takes approximately 2seconds in an “on demand” machine, whereas 0.5 seconds are required forejection of coffee grounds from a collection container in a conventionalgrinder-doser. In case of peak demands of coffee in a bar or restaurant,the coffee grounds dispensing times in an “on demand” machine mightcause delays in beverage preparation.

The Applicant realized that if the grinding-dosing machine is configuredto have a buffer dose available when a winding operation is requested,then the times required for obtaining the doses of coffee grounds forbeverage preparation can be shortened.

In a further mode of operation of the machine, the electronic controlunit is configured to maintain the closure member of the dispensingconduit always in the closed position and to control opening thereofonly upon dispensing of coffee powder into the portafilter. Upon theejection of coffee grounds from the conduit, the control unit instructsclosing of the dispensing conduit and grinding of a buffer dose ofcoffee that builds up in the dispensing conduit.

The coffee grounds dispensing conduit always contains a specific amountof coffee powder, i.e. the buffer dose, which may have been determinedby the operator during calibration. For example, the buffer dose is theminimum dose for preparing a beverage of the plurality of beverages,e.g. a single dose for an espresso.

Once a dose of coffee has been ejected the control unit 97 is configuredto carry out a grinding operation to obtain a buffer dose in the conduit51.

Preferably, the grinding-dosing machine comprises a presence sensorconfigured to detect the presence of the portafilter 4 on the fork 24and removal thereof from the fork once dispensing has been completed.After removal of the portafilter 4, the control unit 97 starts agrinding operation to obtain a new buffer dose in the conduit 51.

The buffer dose in the conduit may be restored after a given time, i.e.the grinding operation has a predetermined duration, which is equal to afirst grinding time stored in the control unit, or based on weightcontrol during dispensing.

In case of buffer dose dispensing with weight control, during thegrinding operation for build-up of a buffer dose, the electronic controlunit is configured to: continuously receive signals representative ofthe weight of coffee grounds built up on the closure member while coffeegrounds are discharged through the conduit, continuously comparing thecoffee grounds weight values associated with the received signals, withthe buffer weight value and stopping the grinding device when a measuredweight value is equal to the buffer weight value.

When the user selects a beverage via the user interface 98 or when therecognition sensor, if an identifier is present in the portafilter,detects the coffee grounds dispensing type, the electronic unit 97checks whether the dispensing type corresponds to the buffer dose thatis already present on the closure member 54. If it does, the controlunit instructs the closure member 54 to open and the coffee powder ismoved into the portafilter. If it does not, the control unit actuatesthe grinding device and carries out a second grinding operation for atime that can provide the nominal dose value that has been selected bythe user.

If the dose required to prepare a selected beverage is a multiple of thebuffer dose, e.g. if the buffer dose corresponds to a single dose andthe filter of the portafilter to be filled corresponds to a double dose,a new dispensing operation has to be carried out to dispense coffee intothe dispensing conduit 51. Here, the time required to obtain a doubledose is reduced to about one half which improves effectiveness of coffeegrounds production for beverage preparation.

In one embodiment, when the central electronic unit detects the presenceof the portafilter by receiving a signal from the presence sensor, theunit actuates the user interface. In the user interface 98, the userselects the button that corresponds to the desired dose by actuating thegrinding operation via the control unit, i.e. by actuating the grinderunit. If the machine also comprises a recognition sensor, the electronicunit will actuate the motor 21 of the grinder unit according to the doseassociated with the identifier. During the grinding operation, the plate54 is kept in the closed position. The grinding operation continuesuntil the load cell senses the weight associated with the selected dose.At the end of the grinding operation, the central unit instructs theplate to open for discharging the dose into the portafilter, and then toclose, and starts a grinding operation for dispensing a buffer dose thatbuilds up again on the plate, waiting for a new request for dispensingof a coffee dose.

Another embodiment does not include weight sensing during the grindingoperation for dispensing a given dose, but includes a grinding operationfor a predetermined grinding time. Such predetermined time is calculatedas a difference between the dispensing time associated with the desireddose and the dispensing time associated with the buffer dose.

In one embodiment, the control unit is configured to control the weightof the buffer dose by receiving a weight signal from the load cell asthe buffer dose has been completely dispensed on the plate. Thus, thebuffer dose is monitored to avoid, undesired deviations.

Certain embodiments provide adjustment of the grinding time as requiredto obtain a buffer dose if the latter deviates from a nominal valuebeyond a predetermined threshold value.

Preferably, a method is provided of controlling the buffer dose ofcoffee, which, comprises: receiving a measurement signal representativeof an actual weight value of coffee grounds built up on the closuremember, the signal being generated at the end of the grinding operation,for dispensing a buffer dose having a buffer weight value; comparing themeasured actual weight value with the stored buffer weight value and,based on the result of the comparison, if the measured actual weightvalue differs from the buffer weight value to an extent exceeding apredetermined threshold value, calculating a mass throughput value basedon the actual weight value and the first grinding time; calculating agrinding time value based on the calculated mass throughout value toobtain the buffer coffee grounds dose value, and storing the calculatedgrinding time value as the new grinding time value associated with thebuffer weight value.

It shall be understood that a person skilled in the art can make manychanges equivalent to the described embodiments without departing fromthe scope of the accompanying claims.

1. A method of method of dispensing a dose of coffee grounds from agrinding-dosing machine, the machine comprising a grinding device whichis configured to grind coffee beans, a dispensing conduit, having aninlet in communication with the grinding device for receiving the coffeegrounds, and an outlet, a closure member which is adapted to be removedbetween an open position for the coffee grounds to be discharged fromthe dispensing conduit through the outlet, and a closed position forclosing the outlet, the method comprising: storing a buffer weight valueand a first grinding time value associated with the buffer weight value;placing the closure member in the closed position; carrying out a firstgrinding operation, by operating the grinding device for a time equal tothe first grinding time, for discharging the coffee grounds through thedispensing conduit so that the amount of the coffee grounds that buildup on the closure member corresponds to the buffer weight value;receiving input data requesting the coffee grounds dispensing,associated with a nominal weight value of the coffee grounds; comparingthe received nominal weight value input with the buffer weight value;based on the comparison result, if the nominal weight value correspondsto the buffer weight value, placing the closure member in the openposition to discharge the coffee grounds built up at the end of thefirst grinding operation through the outlet of the dispensing conduit;based on the comparison result, if the nominal weight value is greaterthan the buffer weight value, carrying out the following steps: with theclosure member maintained in the closed position, carrying out a secondgrinding operation by operating the grinding device to discharge thecoffee grounds through the dispensing conduit onto the closure member;stopping the grinding device when the built-up coffee is equal to thenominal weight value, or at the end of a grinding time associated withthe nominal weight value, and placing the closure member in the openposition to discharge the coffee grounds built up at the end of thefirst and second grinding operations through the outlet of thedispensing conduit.
 2. The method of claim 1, wherein thegrinding-dosing machine further comprises a retaining support for aportafilter, which is configured to support and/or mechanically connecta portafilter, wherein the outlet of the dispensing conduit is placedabove and faces the retaining support, for the coffee grounds to bedischarged into the portafilter when the portafilter is placed on theretaining, support and the closure member is in the open position. 3.The method of claim 1, wherein the grinding dosing machine furthercomprises a weight sensor, which is configured to generate signalsrepresentative of the weight of the coffee grounds built-up in thedispensing conduit when the closure member is in the closed position,the method comprising, during the second grinding operation:continuously receiving measurement signals representative of the weightof the coffee grounds built up on the closure member during discharge ofthe coffee grounds through the dispensing conduit; and continuouslycomparing the weight values of the coffee grounds, associated with thereceived measurement signals, with the nominal weight value of thecoffee grounds, wherein the, grinding device is stopped as soon as aweight value measured by the sensor is equal to the nominal weightvalue.
 4. The method of claim 1, which further comprises, afterreceiving input data requesting the coffee grounds dispensing:associating a nominal grinding time value with the nominal weight valueof the coffee grounds; and calculating a second grinding, time as adifference between the nominal grinding time value and the firstgrinding time, wherein the second grinding operation is carried out fora time equal to the second grinding time and the grinding device isstopped at the end of the second grinding time.
 5. The method of claim1, which comprises, after discharging the coffee grounds built up at theend of the first grinding operation or between the first and the secondgrinding operations, through the outlet of the dispensing conduit:placing the closure member in the closed position; and carrying out afirst grinding operation, by operating the grinding device for a timeequal to the first grinding time, so that the amount of the coffeegrounds that build up on the closure member corresponds to the bufferweight value.
 6. The method of claim 1, wherein the machine furthercomprises a coffee grounds weight sensor, which is configured togenerate measurement signals representative of the weight of the coffeegrounds built-up in the dispensing conduit when the closure member is inthe closed position, the method comprising, after carrying out a firstgrinding operation and before receiving input data requesting the coffeegrounds dispensing: receiving a measurement signal representative of anactual weight value of the coffee grounds built-up on the closure memberat the end of the first grinding operation; comparing the measuredactual weight value with the stored buffer weight value and, based onthe result of the comparison, if the measured actual weight valuediffers from the buffer weight value to an extent exceeding apredetermined threshold value, and calculating a mass throughput valuebased on the actual weight value and the first grinding time;calculating a grinding time value based on the calculated massthroughout value to obtain the buffer coffee grounds dose value; andstoring the calculated grinding time value as the new first grindingtime value for the first grinding operation.
 7. The method of claim 1,wherein the grinding-dosing machine further comprises a weight sensor,which is configured to generate signals representative of the weight ofthe coffee grounds built up in the dispensing conduit when the closuremember is in the closed position, the weight sensor being a load cellconnected to the dispensing conduit and to the closure member so thatthe load cell supports the dispensing conduit and the closure member inhanging relation, wherein the load cell is preferably configured toindicate a zero weight if no coffee grounds are contained in thedispensing conduit.